Config cleanup

[mbukatov]

This a proposed cleanup of test configuration. Documentation with an explanation is provided.

[mbukatov]

This request is based on our discussion from yesterday. @mkudlej @ltrilety @fbalak : Could you review this pull request (github review feature is available in Files changed tab)?

[ltrilety]

I'd like to see options for host and usm config file as special options for pytest. I am planning to make the commit morrow.

[mbukatov]

The more I think about the current design, I feel that the current design is not good:

• we are polluting pytest config namespace
• we would have to change code of config module for every group
• we would need to document how to translate usm.ini name into pytest.ini name

I would rather do this:

• have global config module (eg. usmqe.config) which would be populated during pytest start (in the same way as usmqe.inventory module works right now)

[mbukatov]

We have decided to stay with extending pytest config module, but simplify the process significantly. I'm going to publish an update of this pull request today.

[mbukatov]

I need to test the changes before we can go on, but you can already comment/do a review. @mkudlej

[mbukatov]

I tested the change proposed in this pull request with this simple enviroment (not using mrglog and usmqe assume on purpose) and simple positive scenario works as expected:

$ cat conf/usm.ini 
[usmqepytest]
usm_username = admin
$ cat usmqe_tests/config_cleanup.py
import pytest

def test_config_admin():
    assert pytest.config.getini("usm_username") == "admin"
$ py.test -v usmqe_tests/config_cleanup.py
================================================= test session starts ==================================================
platform linux -- Python 3.5.1, pytest-3.0.4, py-1.4.31, pluggy-0.4.0 -- /opt/rh/rh-python35/root/usr/bin/python3
cachedir: .cache
rootdir: /home/usmqe/usmqe-tests, inifile: pytest.ini
collected 1 items 

usmqe_tests/config_cleanup.py::test_config_admin PASSED

=============================================== 1 passed in 0.01 seconds ==============================================

That said, it fails when I tried to specify the value of the option via command line:

$ py.test -v -o usm_username=foo usmqe_tests/config_cleanup.py
Traceback (most recent call last):
  File "/home/usmqe/.local/lib/python3.5/site-packages/_pytest/config.py", line 1064, in getini
    return self._inicache[name]
KeyError: 'testpaths'

So I need to fix this first.

[mbukatov]

Hmm, it seems to be a py.test issue after all, as I'm able to reproduce this problem in clean setup without any usmqe code: pytest-dev/pytest#2105

On 2016-11-29 we (@mkudlej, @mbukatov, @ltrilety) decided to stay with the ini config options for host and usm config file for now.

[mbukatov]

I just clarified how the override ini feature should be used based on the discussion under the pytest issue. Everything seems to work fine.

[mkudlej]

typo: "mahcine"